Offshore oil and gas wells often produce water together with the desired hydrocarbons. This water stream is referred to as produced water.
At present offshore platforms contain equipment for separating and cleaning produced water to allow for the water to be released to the environment, but this equipment requires platform space which is a limiting factor. The platform will normally comprise equipment to handle hydrocarbon fractions separated from the produced water however the platforms are not always equipped with systems for handling the solid fraction.
In some situations the solids may comprise compounds that may not be released into the environment without further treatment. Equipment for such treatment is normally not installed on the platform and the solids have to be transported to shore or another facility to be treated.
As an alternative to conventional topside processing on a platform, the well stream may be partially processed subsea, and consequently requires treating produced water subsea prior to release back to the environment. Subsea treatment of produced water prevents the seemingly unnecessary transport of produced water from seabed to surface.